Pteridines useful as hcv inhibitors and methods for the preparation thereof

ABSTRACT

The present invention relates to the use of pteridines as inhibitors of HCV replication as well as their use in pharmaceutical compositions aimed to treat or combat HCV infections. In addition, the present invention relates to compounds per se and their use as medicines. The present invention also concerns processes for the preparation of such compounds, pharmaceutical compositions comprising them, and combinations of said compounds with other anti-HCV agents.

The present invention relates to the use of pteridines as inhibitors ofHCV replication as well as their use in pharmaceutical compositionsaimed to treat or combat HCV infections. In addition, the presentinvention relates to compounds per se and their use as medicines. Thepresent invention also concerns processes for the preparation of suchcompounds, pharmaceutical compositions comprising them, and combinationsof said compounds with other anti-HCV agents.

Following its discovery in 1989 as the agent implicated in the majorityof viral non-A, non-B hepatitis (Choo et al., Science 244, 359-362,1989), hepatitis C virus (HCV) has become a focus of considerablemedical research (Lauer, G. M and Walker, B. D., New Eng. J Med. 345,41-52, 2001). HCV is a member of the Flaviviridae family of viruses inthe hepacivirus genus, and is closely related to the flavivirus genus,which includes a number of viruses implicated in human disease, such asdengue virus and yellow fever virus, and to the animal pestivirusfamily, which includes bovine viral diarrhea virus (BVDV). HCV is apositive-sense, single-stranded RNA virus, with a genome of around 9,600bases. The genome comprises both 5′ and 3′ untranslated regions whichadopt RNA secondary structures, and a central open reading frame thatencodes a single polyprotein of around 3,010-3,030 amino acids. Thepolyprotein encodes ten gene products which are generated from theprecursor polyprotein by an orchestrated series of co- andposttranslational endoproteolytic cleavages mediated by both host andviral proteases. The viral structural proteins include the corenucleocapsid protein, and two envelope glycoproteins E1 and E2. Thenon-structural (NS) proteins encode some essential viral enzymaticfunctions (helicase, polymerase, protease), as well as proteins ofunknown function. Replication of the viral genome is mediated by anRNA-dependent RNA polymerase, encoded by non-structural protein 5b(NS5B). In addition to the polymerase, the viral helicase and proteasefunctions, both encoded in the bifunctional NS3 protein, have been shownto be essential for replication of HCV RNA in chimpanzee models ofinfection (Kolykhalov, A. A., Mihalik, K., Feinstone, S. M., and Rice,C. M. J Virol. 74, 2046-2051, 2000). In addition to the NS3 serineprotease, HCV also encodes a metalloproteinase in the NS2 region.

HCV replicates preferentially in hepatocytes but is not directlycytopathic, leading to persistent infection. In particular, the lack ofa vigorous T-lymphocyte response and the high propensity of the virus tomutate appear to promote a high rate of chronic infection. There are 6major HCV genotypes and more than 50 subtypes, which are differentlydistributed geographically. HCV type 1 is the predominant genotype inthe US and Europe. For instance, HCV type 1 accounts for 70 to 75percent of all HCV infections in the United States. The extensivegenetic heterogeneity of HCV has important diagnostic and clinicalimplications, perhaps explaining difficulties in vaccine development andthe lack of response to therapy. An estimated 170 million personsworldwide are infected with hepatitis C virus (HCV). Following theinitial acute infection, a majority of infected individuals developchronic hepatitis, which can progress to liver fibrosis leading tocirrhosis, end-stage liver disease, and HCC (hepatocellular carcinoma)(National Institutes of Health Consensus Development ConferenceStatement: Management of Hepatitis C. Hepatology, 36, 5 Suppl. S3-S20,2002). Liver cirrhosis due to HCV infection is responsible for about10,000 deaths per year in the U.S.A. alone, and is the leading cause forliver transplantations. Transmission of HCV can occur through contactwith contaminated blood or blood products, for example following bloodtransfusion or intravenous drug use. The introduction of diagnostictests used in blood screening has led to a downward trend inpost-transfusion HCV incidence. However, given the slow progression tothe end-stage liver disease, the existing infections will continue topresent a serious medical and economic burden for decades (Kim, W. R.Hepatology, 36, 5 Suppl. S30-S34, 2002).

The treatment of this chronic disease is an unmet clinical need, sincecurrent therapy is only partially effective and limited by undesirableside effects.

Current HCV therapies are based on (pegylated) interferon-alpha (IFN-α)in combination with ribavirin. This combination therapy yields asustained virologic response in more than 40% of patients infected bygenotype 1 viruses and about 80% of those infected by genotypes 2 and 3.Beside the limited efficacy on HCV type 1, combination therapy hassignificant side effects and is poorly tolerated in many patients. Forinstance, in registration trials of pegylated interferon and ribavirin,significant side effects resulted in discontinuation of treatment inapproximately 10 to 14 percent of patients. Major side effects ofcombination therapy include influenza-like symptoms, hematologicabnormalities, and neuropsychiatric symptoms. The development of moreeffective, convenient and tolerated treatments is a major public healthobjective.

Thus, there is a high medical need for low molecular weight compoundsthat lead to an inhibition of HCV replication.

It has been surprisingly found that derivatives of pteridines exhibitantiviral activity in mammals infected with HCV, in particular thesederivatives inhibit HCV replication. These compounds are thereforeuseful in treating or combating HCV infections.

US20040038856 discloses methods of treating fibroproliferative disordersassociated with TGF-β signaling, by administering non-peptide smallmolecule inhibitors of TGF-β specifically binding to the type I TGF-βreceptor (TGFβ-R1). The inhibitors are preferably quinazolinederivatives.

WO04/048930 further describes methods for counteracting a loss inβ-adrenergic sensitivity in the β-adrenergic signal transduction pathwayby administering an effective amount of a compound capable of inhibitingTGF-β signaling through a TGF-β receptor.

WO04/065392 relates to condensed pyridines and pyrimidines and their useas ALK-5 receptor ligands. In particular, the invention disclosestherapeutically active substituted quinoline and quinazoline compounds,the use thereof in therapy, particularly in the treatment or prophylaxisof disorders characterised by overexpression of transforming growthfactor β (TGF-β), and pharmaceutical compositions for use in suchtherapy.

After initial exposure to the Hepatitis C virus, HCV RNA can be detectedin blood in 1-3 weeks. Within an average of 50 days virtually allpatients develop liver cell injury. The majority of patients areasymptomatic and anicteric. Only 25-35 percent develop malaise,weakness, or anorexia, and some become icteric. Antibodies to HCV(anti-HCV) almost invariably become detectable during the course ofillness. Anti-HCV can be detected in 50-70 percent of patients at theonset of symptoms and in approximately 90 percent of patients 3 monthsafter onset of infection. HCV infection is self-limited in only 15percent of cases. Recovery is characterized by disappearance of HCV RNAfrom blood and return of liver enzymes to normal.

About 85 percent of HCV-infected individuals fail to clear the virus by6 months and develop chronic hepatitis with persistent, althoughsometimes intermittent, viremia. This capacity to produce chronichepatitis is one of the most striking features of HCV infection. Chronichepatitis C is typically an insidious process, progressing, if at all,at a slow rate without symptoms or physical signs in the majority ofpatients during the first two decades after infection. Symptoms firstappear in many patients with chronic hepatitis C at the time ofdevelopment of advanced liver disease.

In chronic hepatitis, inflammatory cells infiltrate the portal tractsand may also collect in small clusters in the parenchyma. The latterinstance is usually accompanied by focal liver cell necrosis. The marginof the parenchyma and portal tracts may become inflamed, with liver cellnecrosis at this site (interface hepatitis). If and when the diseaseprogresses, the inflammation and liver cell death may lead to fibrosis.Mild fibrosis is confined to the portal tracts and immediately adjacentparenchyma. More severe fibrosis leads to bridging between portal tractsand between portal tracts and hepatic veins. Such fibrosis can progressto cirrhosis, defined as a state of diffuse fibrosis in which fibrousseptae separate clusters of liver cells into nodules. The extent offibrosis determines the stage of disease and can be reliably assessed.Severe fibrosis and necroinflammatory changes predict progression tocirrhosis. Once cirrhosis is established, complications can ensue thatare secondary to liver failure and/or to portal hypertension, such asjaundice, ascites, variceal hemorrhage, and encephalopathy. Thedevelopment of any of these complications marks the transition from acompensated to a decompensated cirrhosis.

Chronic hepatitis C infection leads to cirrhosis in at least 20 percentof patients within 2 decades of the onset of infection. Cirrhosis andend-stage liver disease may occasionally develop rapidly, especiallyamong patients with concomitant alcohol use. Chronic infection by HCV isassociated with an increased risk of liver cancer. The prevailingconcept is that hepatocellular carcinoma (HCC) occurs against abackground of inflammation and regeneration associated with chronichepatitis over the course of approximately 3 or more decades. Most casesof HCV-related HCC occur in the presence of cirrhosis.

Liver fibrosis is one of the processes that occurs when the liver isdamaged. Such damage may be the result of viral activity (e.g., chronichepatitis types B or C) or other liver infections (e.g., parasites,bacteria); chemicals (e.g., pharmaceuticals, recreational drugs,excessive alcohol, exposure to pollutants); immune processes (e.g.,autoimmune hepatitis); metabolic disorders (e.g., lipid, glycogen, ormetal storage disorders); or cancer growth (primary or secondary livercancer). Fibrosis is both a sign of liver damage and a potentialcontributor to liver failure via progressive cirrhosis of the liver.

It has been disclosed that the inhibition of the family of TGFβ kinasesis useful in the treatment of fibroproliferative disorders, includingliver fibrosis. However, as it is noted above, liver fibrosis may becaused by different ethiological agents, including the Hepatitis Cvirus. Most importantly, liver fibrosis is a specific condition in thedisease progression of patients infected with HCV.

It has been surprisingly found that the compounds of the presentinvention inhibit HCV replication. HCV replication refers to the processof reproducing or making copies of HCV RNA. In the present invention HCVreplication both refers to the replication of the HCV virus as a wholeor the replication of the HCV RNA genome.

It is important to treat HCV infected patients at early stages in orderto avoid disease progression, thereby avoiding that the patient developschronic hepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma(HCC), or death.

In addition, the compounds of the invention are valuable in that theymay diminish the HCV viral load of a patient to undetected levels.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the mean plasma and tissue concentrations (n=3) ofcompound nr. 21 after a single oral administration at 20 mg base-eq./kgin the male Swiss SPF (CD1)-mice.

DISCLOSURE OF THE INVENTION

The present invention thus relates to the use of a compound of theformula (I) for the manufacture of a medicament useful for inhibitingHCV activity in a mammal infected with HCV. Said compound is a pteridineof the formula (I):

-   -   an N-oxide, salt, stereoisomeric form, racemic mixture, prodrug,        ester or metabolite thereof, wherein    -   R¹ is independently hydrogen, amino, mono- or disubstituted        amino, wherein the substituent(s) of the amino may be selected        from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₄alkoxyC₁₋₄alkyl,        diC₁₋₄alkylaminoC₁₋₄alkyl, piperidin-1-yl-C₁₋₄alkyl,        arylC₁₋₆alkyl, wherein the aryl group may be further substituted        with C₁₋₄alkyl, or C₁₋₄alkoxy;    -   L is —NR⁸—, —NR⁸—C₁₋₆alkanediyl-, —NR⁸—CO—C₁₋₆alkanediyl-,        —NR⁸—SO₂— C₁₋₆alkanediyl-, —O—, —O—C₁₋₆alkanediyl-, —O—CO—,        —O—CO—C₁₋₆alkanediyl-, —S—, —S—C₁₋₆alkanediyl-, or

-   -   wherein the dotted ring together with N and Z form a Het¹ cycle        having 5 to 8 members including ring members N and Z, and        wherein said L ring is attached to the pteridine ring by the        nitrogen atom;    -   Z represents N or CH;    -   R² represents hydrogen, hydroxyC₁₋₆alkyl, C₃₋₇cycloalkyl, aryl,        Het¹, or Het², wherein said C₃₋₇cycloalkyl, aryl, Het¹, and Het²        are each independently optionally substituted with one or more        substituents selected from C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl,        polyhaloC₁₋₄alkyl, halo, cyano, nitro, —COR⁶, —COOR⁷,        —CONR^(4a)R^(4b), —OR⁷, —OCOR⁶, —OCONR^(4a)R^(4b),        —NR^(4a)R^(4b), —NR^(4a)COR⁶, —NR^(4a)CONR^(4a)R^(4b),        —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵, —SR⁵, —SOR⁷, —SO₂R⁵, —SO₃R⁷,        —SO₂NR^(4a)R^(4b), morpholin-4-yl, phenyl, aminophenyl, and        aminophenylcarbonyl, and wherein the C₁₋₄alkyl may be further        substituted with —COOR⁷;    -   R³ represents a C₁₋₆alkyl, C₃₋₇cycloalkyl, aryl, arylC₁₋₆alkyl,        Het¹, Het²or Het²-C₁₋₆alkyl, each independently optionally        substituted with one or more substituents selected from        C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl, polyhaloC₁₋₄alkyl, halo,        cyano, nitro, —COR⁶, —COOR⁷, —CONR^(4a)R^(4b), —OR⁷, —OCOR⁶,        —OCONR^(4a)R^(4b), —NR^(4a)R^(4b), NR^(4a)COR⁶, —NR^(4a)COOR⁷,        —NR^(4a)CONR^(4a)R^(4b), —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵, —SR⁵,        —SOR⁷, —SO₂R⁵, —SO₃R⁷, —SO₂NR^(4a)R^(4b); and wherein R^(4a) and        R^(4b) may optionally form, together with the nitrogen atom to        which they are bound, a 5 to 8 membered saturated, unsaturated        or partially unsaturated ring, optionally comprising one or two        additional heteroatoms;    -   each R^(4a) and R^(4b) is independently hydrogen, C₁₋₄alkyl,        hydroxyC₁₋₄alkyl, Het¹ polyhaloC₁₋₄alkyl, cyano, or nitro;    -   each R⁵ is independently hydrogen, or C₁₋₄alkyl;    -   each R⁶ is independently hydrogen, or C₁₋₄alkyl;    -   each R⁷ is independently hydrogen, or C₁₋₄alkyl; and    -   R⁸ is hydrogen, C₁₋₁₀alkyl, C₂₋₁₀alkenyl, C₂₋₁₀alkynyl,        C₁₋₁₀alkylcarbonyl, amino-C₁₋₁₀alkyl, aryl, arylcarbonyl,        arylC₁₋₁₀alkyl, Het¹, Het¹C₁₋₆alkyl, or a protecting group,        wherein the aryl is optionally substituted with 1 to 3        substituents selected from C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl,        C₁₋₄alkylcarbonyl, phenyl, C₁₋₄alkylphenyl, phenylcarbonyl,        aminophenyl, aminoC₁₋₄alkylphenyl, aminophenylcarbonyl, halo,        —OR⁶, —NR^(4a)R^(4b), —SR⁵, —SOR⁵, —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵,        —SO₂R⁵, —OCOR⁶, —NR^(4a)COR⁶, —NR^(4a)CONR^(4a)R^(4b),        —NR^(4a)COOR⁶, C₁₋₄alkyl, and nitro;

Het¹ as a group or part of a group is defined as a saturated orpartially unsaturated monocyclic, bicyclic or tricyclic heterocyclehaving preferably 3 to 12 ring members, more preferably 5 to 10 ringmembers and more preferably 5 to 8 ring members, which contains one ormore heteroatom ring members selected from nitrogen, oxygen or sulfurand which is optionally substituted on one or more carbon atoms byC₁₋₆alkyl, C₁₋₆alkoxy, halo, hydroxy, oxo, optionally mono- ordisubstituted amino, nitro, cyano, polyhaloC₁₋₄alkyl, carboxyl,C₁₋₆alkoxy-carbonyl, C₃₋₇cycloalkyl, optionally mono- or disubstitutedaminocarbonyl, methylthio, methylsulfonyl, aryl and a saturated orpartially unsaturated monocyclic, bicyclic or tricyclic heterocyclehaving 3 to 12 ring members which contains one or more heteroatom ringmembers selected from nitrogen, oxygen or sulfur and whereby theoptional substituents on any amino function are hydrogen, or C₁₋₄alkyl;

Het² as a group or part of a group is defined as an aromatic monocyclic,bicyclic or tricyclic heterocycle having 3 to 14 ring members,preferably 5 to 10 ring members and more preferably 5 to 6 ring members,which contains one or more heteroatom ring members each independentlyselected from nitrogen, oxygen or sulfur, and which is optionallysubstituted on one or more carbon atoms by C₁₋₆alkyl, optionally mono-or disubstituted aminoC₁₋₆alkyl, hydroxyC₁₋₆alkyl, C₁₋₆alkoxy, halo,hydroxy, optionally mono- or disubstituted amino, nitro, cyano,polyhalo-C₁₋₄alkyl, carboxyl, C₁₋₆alkoxycarbonyl, C₃₋₇cycloalkyl,optionally mono- or disubstituted aminocarbonyl, methylthio,methylsulfonyl, aryl, Het¹ and an aromatic monocyclic, bicyclic ortricyclic heterocycle having 3 to 12 ring members; whereby the optionalsubstituents on any amino function are hydrogen, or C₁₋₄alkyl; and

-   -   aryl as a group or part of a group is phenyl.

The present invention further relates to the use of a compound of theformula (II) for the manufacture of a medicament useful for inhibitingHCV activity in a mammal infected with HCV. Said compound is a pteridineof the formula (II):

-   -   an N-oxide, salt, stereoisomeric form, racemic mixture, prodrug,        ester or metabolite thereof; wherein R¹, R³, R^(4a), R^(4b), R⁵,        R⁶, R⁷, R⁸, Het¹, and Het² have the meaning as indicated above;        wherein    -   R⁹ represents C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl,        polyhaloC₁₋₄alkyl, halo, cyano, nitro, —COR⁶, —COOR⁷,        —CONR^(4a)R^(4b), —OR⁷, —OCOR⁶, —OCONR^(4a)R^(4b),        —NR^(4a)R^(4b), —NR^(4a)COR⁶, —NR^(4a)CONR^(4a)R^(4b),        —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵, —SR⁵, —SOR⁷, —SO₂R⁵, —SO₃R⁷,        —SO₂NR^(4a)R^(4b), morpholin-4-yl, phenyl, aminophenyl, or        aminophenyl-carbonyl, and wherein the C₁₋₄alkyl may be further        substituted with —COOR⁷; and    -   n is 0, 1, 2, 3, or 4.

The present invention further relates to the use of a compound of theformula (III) for the manufacture of a medicament useful for inhibitingHCV activity in a mammal infected with HCV. Said compound is a pteridineof the formula (III):

-   -   an N-oxide, salt, stereoisomeric form, racemic mixture, prodrug,        ester or metabolite thereof; wherein R¹, L, R², R^(4a), R^(4b),        R⁵, R⁶, R⁷, R⁸, Het¹, and Het² have the meaning as indicated        above; wherein    -   R¹⁰ represents C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl,        polyhaloC₁₋₄alkyl, halo, cyano, nitro, —COR⁶, —COOR⁷,        —CONR^(4a)R^(4b), —OR⁷, —OCOR⁶, —OCONR^(4a)R^(4b),        —NR^(4a)R^(4b), —NR^(4a)COR⁶, —NR^(4a)COOR⁷,        —NR^(4a)CONR^(4a)R^(4b), —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵, —SR⁵,        —SOR⁷, —SO₂R⁵, —SO₃R⁷, and —SO₂NR^(4a)R^(4b); and    -   m is 0, 1, 2, 3, or 4.

The present invention further relates to the use of a compound of theformula (IV) for the manufacture of a medicament useful for inhibitingHCV activity in a mammal infected with HCV. Said compound is a pteridineof the formula (IV):

-   -   an N-oxide, salt, stereoisomeric form, racemic mixture, prodrug,        ester or metabolite thereof, wherein R¹, R^(4a), R^(4b), R⁵, R⁶,        R⁷, R⁸, Het¹, and Het² have the meaning as indicated above;        wherein    -   R⁹ represents C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl,        polyhaloC₁₋₄alkyl, halo, cyano, nitro, —COR⁶, —COOR⁷,        —CONR^(4a)R^(4b), —OR⁷, —OCOR⁶, —OCONR^(4a), R^(4b),        —NR^(4a)R^(4b), —NR^(4a)COR⁶, —NR^(4a)CONR^(4a)R^(4b),        —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵, —SR⁵, —SOR⁷, —SO₂R⁵, —SO₃R⁷,        —SO₂NR^(4a)R^(4b), morpholin-4-yl, phenyl, aminophenyl, or        aminophenyl-carbonyl, and wherein the C₁₋₄alkyl may be further        substituted with —COOR⁷;    -   R¹⁰ represents C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl,        polyhaloC₁₋₄alkyl, halo, cyano, nitro, —COR⁶, —COOR⁷,        —CONR^(4a)R^(4b), —OR⁷, —OCOR⁶, —OCONR^(4a)R^(4b),        —NR^(4a)R^(4b), —NR^(4a)COR⁶, —NR^(4a)COOR⁷,        —NR^(4a)CONR^(4a)R^(4b), —NR^(4a)SOR⁵, —NR^(4a)SO₂R⁵, —SR⁵,        —SOR⁷, —SO₂R⁵, —SO₃R⁷, and —SO₂NR^(4a)R^(4b);    -   n is 0, 1, 2, 3, or 4; and    -   m is 0, 1, 2, 3, or 4.

The present invention further relates to the use of a compound of theformula (V) for the manufacture of a medicament useful for inhibitingHCV activity in a mammal infected with HCV. Said compounds arepteridines of the formula (V):

-   -   a salt, stereoisomeric form, and racemic mixture thereof,        wherein    -   R¹ is hydrogen or amino;    -   R⁸ is hydrogen, C₁₋₆alkyl, aminoC₁₋₄alkyl, phenylC₁₋₄alkyl,        pyrrolidin-1-yl-C₁₋₄alkyl, or C₁₋₆alkoxycarbonyl;    -   each R⁹ represents, independently, hydrogen, C₁₋₄alkyl, —COR⁶,        —COOR⁷, or —CONR^(4a)R^(4b);    -   n is 0, 1, 2, 3, or 4;    -   R¹¹ represents hydrogen, halo, or —NR^(4a)R^(4b), wherein R^(4a)        and R^(4b) may optionally form, together with the nitrogen atom        to which they are bound, a 5 to 8 membered saturated,        unsaturated or partially unsaturated ring, optionally comprising        one or two additional heteroatoms;    -   R¹² represents hydrogen, halo, C₁₋₄alkyl, or polyhaloC₁₋₄alkyl;    -   R⁶ is hydrogen, or C₁₋₄alkyl;    -   R⁷ is hydrogen, or C₁₋₄alkyl; and    -   R^(4a) and R^(4b), independently, are hydrogen, C₁₋₄alkyl,        2-oxo-pyrrolidin-1-yl-C₁₋₄alkyl.

One embodiment relates to the use of the compounds of formulae (II),(IV), or (V) as specified above, wherein n is 1.

In a further aspect the invention relates to a method of inhibiting HCVreplication in a mammal infected with HCV, said method comprising theadministration of an HCV inhibitory effective amount of a compound offormulae (I), (II), (III), (W), or (V) as specified above or as furtherspecified hereinafter. In a particular embodiment, the method ofinhibiting HCV replication in a mammal infected with HCV comprises theadministration of an HCV inhibitory effective amount of a compound offormulae (II), (IV), or (V) wherein n is 1.

In a further aspect the invention relates to a method of treating amammal infected with HCV, said method comprising the administration ofan HCV inhibitory effective amount of a compound of formulae (I), (II),(III), (IV), or (V) as specified above or as further specifiedhereinafter. In a particular embodiment, the method of treating a mammalinfected with HCV comprises the administration of an HCV inhibitoryeffective amount of a compound of formulae (II), (IV), or (V) wherein nis 1.

In a further embodiment, the present invention relates to the use of acompound of the formula (VI) for the manufacture of a medicament forinhibiting HCV replication in a mammal infected with HCV. Said compoundis a pteridine of the formula (VI):

-   -   a salt, stereoisomeric form, and racemic mixture thereof,        wherein R¹, R⁸, R⁹, R¹¹, R¹², R⁶ are as defined above.

In a further embodiment the invention relates to a method of inhibitingHCV replication in a mammal infected with HCV, said method comprisingthe administration of an HCV inhibitory effective amount of a compoundof formula (VI) as specified above or as further specified hereinafter.

In a further embodiment the invention relates to a method of treating amammal infected with HCV, said method comprising the administration ofan HCV inhibitory effective amount of a compound of formula (VI) asspecified above or as further specified hereinafter.

Still further embodiments of the invention relate to the use of thecompounds of the formulae (V) or (VI) for the manufacture of amedicament for inhibiting HCV replication in a mammal infected with HCV.Said compounds are pteridines of the formulae (V) or (VI) wherein, whereapplicable n is 1, and

R¹ is hydrogen or amino;

R⁸ is hydrogen, C₁₋₆alkyl, phenylC₁₋₄alkyl;

R⁹ represents hydrogen, C₁₋₄alkyl, —COR⁶, —COOR⁷, or —CONR^(4a)R^(4b);

R¹¹ represents hydrogen, fluoro, or pyrrolidin-1-yl;

R¹² represents halo, C₁₋₄alkyl, or polyhaloC₁₋₄alkyl;

R⁶ is hydrogen, or C₁₋₄alkyl;

R⁷ is hydrogen, or C₁₋₄alkyl; and

R^(4a) and R^(4b), independently, are hydrogen, C₁₋₄alkyl,2-oxo-pyrrolidin-1-yl-C₁₋₄alkyl.

Further embodiments of the invention relate to the method of inhibitingHCV replication in a mammal infected with HCV, and to the method oftreating a mammal infected with HCV, said methods comprising theadministration of an HCV inhibitory effective amount of a compound offormulae (V) or (VI) wherein, where applicable n is 1, and R¹, R⁸, R⁹,R¹¹, R¹² are as defined in the previous paragraph.

Yet still further embodiments of the invention relate to the use of thecompounds of the formulae (V) or (VI) for the manufacture of amedicament for inhibiting HCV replication in a mammal infected with HCV.Said compounds are pteridines of the formulae (V) or (VI) wherein, whereapplicable n is 1, and

R¹ is hydrogen;

R⁸ is hydrogen, C₁₋₆alkyl, phenylC₁₋₄alkyl;

R⁹ represents hydrogen, C₁₋₄alkyl, or —COOR⁷;

R¹¹ represents fluoro, or pyrrolidin-1-yl;

R¹² represents halo, or C₁₋₄alkyl; and

R⁷ is hydrogen, or C₁₋₄alkyl.

Thus, further embodiments of the invention relate to a method ofinhibiting HCV replication in a mammal infected with HCV, and to amethod of treating a mammal infected with HCV, said methods comprisingthe administration of an HCV inhibitory effective amount of a compoundof formulae (V) or (VI) wherein, where applicable n is 1, and R¹, R⁸,R⁹, R¹¹, R¹² are as defined in the previous paragraph.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VII):

a salt, stereoisomeric form, and racemic mixture thereof, wherein

R¹ is hydrogen or amino;

R⁸ is hydrogen, C₁₋₆alkyl, phenylC₁₋₄alkyl;

R⁹ represents hydrogen, C₁₋₄alkyl, —COR⁶, COOR⁷, or —CONR^(4a)R^(4b);

R⁶ is independently hydrogen, or C₁₋₄alkyl;

each R⁷ is independently hydrogen, or C₁₋₄alkyl; and

each R^(4a) and R^(4b) is independently hydrogen, C₁₋₄alkyl,2-oxo-pyrrolidin-1-yl-C₁₋₄alkyl;

with the proviso that when R⁸ is hydrogen, R⁹ is not hydrogen.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VII), a salt, stereoisomeric form, and racemic mixturethereof, wherein

R⁸ is C₁₋₆alkyl, phenylC₁₋₄alkyl;

R¹, R^(4a), R^(4b), R⁶, R⁷, and R⁹ are as recited in the previousparagraph.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VII), a salt, stereoisomeric form, and racemic mixturethereof, wherein

R⁹ represents C₁₋₄alkyl, —COR⁶, COOR⁷, or —CONR^(4a)R^(4b);

R¹, R^(4a), R^(4b), R⁶, R⁷, and R⁸ are as recited in the second previousparagraph.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VIII):

a salt, stereoisomeric form, and racemic mixture thereof, wherein

R¹ is independently hydrogen or amino;

R⁸ is hydrogen, C₁₋₆alkyl, phenylC₁₋₄alkyl;

R⁹ represents hydrogen, C₁₋₄alkyl, —COR⁶, COOR⁷, or —CONR^(4a)R^(4b);

R⁶ is independently hydrogen, or C₁₋₄alkyl;

each R⁷ is independently hydrogen, or C₁₋₄alkyl; and

each R^(4a) and R^(4b) is independently hydrogen, C₁₋₄alkyl, with theproviso that when R⁸ is hydrogen, R⁹ is not hydrogen.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VIII), a salt, stereoisomeric form, and racemic mixturethereof, wherein

R⁹ represents C₁₋₄alkyl, —COR⁶, COOR⁷, or —CONR^(4a)R^(4b);

R¹, R^(4a), R^(4b), R⁶, R⁷, and R⁸ are as recited in the previousparagraph.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VIII), a salt, stereoisomeric form, and racemic mixturethereof, wherein

R⁸ is C₁₋₆alkyl, phenylC₁₋₄alkyl;

R¹, R^(4a), R^(4b), R⁶, R⁷, and R⁹ are as recited in the second previousparagraph.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VII) or (VIII) as set forth above, wherein

R¹ is hydrogen;

R⁸ is hydrogen;

R⁹ represents C₁₋₄alkyl.

In a further embodiment, the present invention relates to a pteridine ofthe formula (VII) or (VIII) as set forth above, wherein

R¹ is hydrogen;

R⁸ is C₁₋₆alkyl;

R⁹ represents hydrogen.

A method of treating clinical conditions relating to HCV infection in amammal, said method comprising the administration of an HCV inhibitoryeffective amount of a compound of formula (V) wherein R¹, R⁸, R⁹, R¹¹,R¹² are as defined hereinafter.

A method as in the previous paragraph wherein the clinical conditionsare other than liver fibrosis.

The compounds of formulae (I), (II), (III), (IV), (V), (VI), (VII), and(VIII) show activity against the HCV virus and are therefore useful as amedicament, and in the manufacture of a medicament for preventing,treating or combating infection, clinical conditions, or a diseaseassociated with HCV infection.

The compounds of formulae (I), (II), (III), (IV), (V), (VI), (VII), and(VIII) show activity against the HCV virus and are therefore useful as amedicament, and in the manufacture of a medicament for preventing,treating or combating clinical conditions associated with HCV infectionother than liver fibrosis.

The term “C₁₋₂alkyl” as a group or part of a group defines straight andbranched chained saturated hydrocarbon radicals having from 1 to 2carbon atoms, such as, for example, methyl, ethyl, and the like.

The term “C₁₋₄alkyl” as a group or part of a group defines straight andbranched chained saturated hydrocarbon radicals having from 1 to 4carbon atoms, such as, for example, the groups defined for C₁₋₂alkyl andpropyl, butyl, 2-methyl-propyl and the like.

The term “C₁₋₆alkyl” as a group or part of a group defines straight andbranched chained saturated hydrocarbon radicals having from 1 to 6carbon atoms such as, for example, the groups defined for C₁₋₄alkyl andpentyl, hexyl, 2-methylbutyl, 3-methylpentyl and the like.

The term “C₁₋₁₀alkyl” as a group or part of a group defines straight andbranched chained saturated hydrocarbon radicals having from 1 to 10carbon atoms such as, for example, the groups defined for C₁₋₆alkyl andheptyl, octyl, nonyl, decyl and the like.

The term “C₂₋₄alkenyl” as a group or part of a group defines straightand branched chained hydrocarbon radicals having saturated carbon-carbonbonds and at least one double bond, and having from 2 to 4 carbon atoms,such as, for example, ethenyl, prop-1-enyl, but-1-enyl, but-2-enyl, andthe like. Preferred are C₂₋₄alkenyls having one double bond.

The term “C₂₋₆alkenyl” as a group or part of a group defines straightand branched chained hydrocarbon radicals having saturated carbon-carbonbonds and at least one double bond, and having from 2 to 6 carbon atoms,such as, for example, the groups defined for C₂₋₄alkenyl andpent-1-enyl, pent-2-enyl, hex-1-enyl, hex-2-enyl, hex-3-enyl,1-methyl-pent-2-enyl and the like. Preferred are C₂₋₆alkenyls having onedouble bond.

The term “C₂₋₁₀alkenyl” as a group or part of a group defines straightand branched chained hydrocarbon radicals having saturated carbon-carbonbonds and at least one double bond, and having from 2 to 10 carbonatoms, such as, for example, the groups defined for C₂₋₆alkenyl andhept-1 -enyl, hept-2-enyl, 2-methyl-hept-1 -enyl, oct-3-enyl,non-4-enyl, 1-methyl-non-2-enyl and the like. Preferred areC₂₋₁₀alkenyls having one double bond.

The term “C₂₋₄alkynyl” as a group or part of a group defines straightand branched chained hydrocarbon radicals having saturated carbon-carbonbonds and at least one triple bond, and having from 2 to 4 carbon atoms,such as, for example, ethynyl, prop-1-ynyl, but-1-ynyl, but-2-ynyl, andthe like. Preferred are C₂₋₄alkynyls having one triple bond.

The term “C₂₋₆alkynyl” as a group or part of a group defines straightand branched chained hydrocarbon radicals having saturated carbon-carbonbonds and at least one triple bond, and having from 2 to 6 carbon atoms,such as, for example, the groups defined for C₂₋₄alkynyl andpent-1-ynyl, pent-2-ynyl, hex-1-ynyl, hex-2-ynyl, hex-3-ynyl,1-methyl-pent-2-ynyl, pent-2-en-4-ynyl and the like. Preferred areC₂₋₆alkynyls having one triple bond.

The term “C₂₋₁₀alkynyl” as a group or part of a group defines straightand branched chained hydrocarbon radicals having saturated carbon-carbonbonds and at least one triple bond, and having from 2 to 10 carbonatoms, such as, for example, the groups defined for C₂₋₆alkynyl andhept-1-ynyl, hept-2-ynyl, 2-methyl-hept-1-ynyl, oct-3-ynyl, non-4-ynyl,1-methyl-non-2-ynyl and the like. Preferred are C₂₋₁₀alkynyls having onetriple bond.

The term “C₁₋₆alkanediyl” as a group or part of a group defines bivalentstraight and branched chained hydrocarbons having from 1 to 6 carbonatoms such as, for example, methanediyl, 1,2-ethanediyl, or1,1-ethanediyl, 1,3-propanediyl, 1,3-butanediyl, 1,4-butanediyl, 1,3-pentanediyl, 1,5-pentanediyl, 1,4-hexanediyl, 1,6-hexanediyl, and thelike.

The term “C₃₋₇cycloalkyl” is generic to cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl and cycloheptyl.

The term “aryl” as a group or part of a group is meant to include phenylor naphtyl. In a preferred embodiment, the term “aryl” as a group orpart of a group is phenyl.

The term “halo” is generic to fluoro, chloro, bromo or iodo.

As used in the foregoing and hereinafter “polyhaloC₁₋₄alkyl” as a groupor part of a group is defined as mono- or polyhalosubstituted C₁₋₄alkyl,for example, 1,1,1-trifluoroethyl, 1,1-difluoro-ethyl, thepolyhalomethyl groups mentioned hereinafter, and the like. A preferredsubgroup of polyhaloC₁₋₄alkyl is polyhalomethyl, wherein the latter as agroup or part of a group is defined as mono- or polyhalo-substitutedmethyl, in particular methyl with one or more fluoro atoms, for example,difluoromethyl or trifluoromethyl. In case more than one halogen atom isattached to an alkyl group within the definition of polyhalomethyl orpolyhaloC₁₋₄alkyl, they may be the same or different.

The term “protecting group” refers to an amino-protecting group such assuch as C₁₋₁₀alkoxy-carbonyl, arylC₁₋₁₀alkoxy-carbonyl, like benzoyl,anisoyl-, isobutyroyl-, acetyl-, or tert-butylbenzoyl (Breipohl et al.(1997) Tetrahedron 53, 14671-14686). The protecting group may be as wellan acid-labile protecting group such as dimethoxytrityl.

It should also be noted that the radical positions on any molecularmoiety used in the definitions, unless indicated otherwise, may beanywhere on such moiety as long as it is chemically stable. For instancepyridyl includes 2-pyridyl, 3-pyridyl and 4-pyridyl; pentyl includes1-pentyl, 2-pentyl and 3-pentyl.

When any variable (e.g. halogen or C₁₋₄alkyl) occurs more than one timein any constituent, each definition is independent.

The N-oxide forms of the present compounds are meant to comprise any oneof the compounds of the present invention wherein one or severalnitrogen atoms are oxidized to the so-called N-oxide.

For therapeutic use, the salts of the compounds of the present inventionare those wherein the counter-ion is pharmaceutically or physiologicallyacceptable. However, salts having a pharmaceutically unacceptablecounter-ion may also find use, for example, in the preparation orpurification of a pharmaceutically acceptable compound of the presentinvention. All salts, whether pharmaceutically acceptable or not areincluded within the ambit of the present invention.

The pharmaceutically acceptable or physiologically tolerable additionsalt forms which the compounds of the present invention are able to formcan conveniently be prepared using the appropriate acids, such as, forexample, inorganic acids such as hydrohalic acids, e.g. hydrochloric orhydrobromic acid, sulfuric, hemisulphuric, nitric, phosphoric and thelike acids; or organic acids such as, for example, acetic, aspartic,dodecyl-sulphuric, heptanoic, hexanoic, benzoic, nicotinic, propanoic,hydroxyacetic, lactic, pyruvic, oxalic, malonic, succinic, maleic,fumaric, malic, tartaric, citric, methanesulfonic, ethanesulfonic,benzenesulfonic, p-toluenesulfonic, cyclamic, salicylic,p-amino-salicylic, pamoic and the like acids.

Conversely said acid addition salt forms can be converted by treatmentwith an appropriate base into the free base form.

The compounds of the present invention containing an acidic proton mayalso be converted into their non-toxic metal or amine addition base saltform by treatment with appropriate organic and inorganic bases.Appropriate base salt forms comprise, for example, the ammonium salts,the alkali and earth alkaline metal salts, e.g. the lithium, sodium,potassium, magnesium, calcium salts and the like, salts with organicbases, e.g. the benzathine, N-methyl-D-glucamine, hydrabamine salts, andsalts with amino acids such as, for example, arginine, lysine and thelike. Alternatively, when a carboxyl moiety is present on a compound ofthe present invention, the compound may also be supplied as a salt witha pharmaceutically acceptable cation.

Conversely said base addition salt forms can be converted by treatmentwith an appropriate acid into the free acid form.

The term “salts” also comprises the hydrates and the solvent additionforms that the compounds of the present invention are able to form.Examples of such forms are e.g. hydrates, alcoholates and the like.

In the event that any of the substituents of the compounds of thepresent invention contain chiral centers, as some, indeed, do, thecompounds the present invention include all stereoisomeric formsthereof, both as isolated stereoisomers and mixtures of thesestereoisomeric forms.

The term stereochemically isomeric forms of compounds of the presentinvention, as used hereinbefore, defines all possible compounds made upof the same atoms bonded by the same sequence of bonds but havingdifferent three-dimensional structures which are not interchangeable,which the compounds of the present invention may possess. Unlessotherwise mentioned or indicated, the chemical designation of a compoundencompasses the mixture of all possible stereochemically isomeric formswhich said compound may possess. Said mixture may contain alldiastereomers and/or enantiomers of the basic molecular structure ofsaid compound. All stereochemically isomeric forms of the compounds ofthe present invention both in pure form or in admixture with each otherare intended to be embraced within the scope of the present invention.

Pure stereoisomeric forms of the compounds and intermediates asmentioned herein are defined as isomers substantially free of otherenantiomeric or diastereomeric forms of the same basic molecularstructure of said compounds or intermediates. In particular, the term‘stereoisomerically pure’ concerns compounds or intermediates having astereoisomeric excess of at least 80% (i. e. minimum 90% of one isomerand maximum 10% of the other possible isomers) up to a stereoisomericexcess of 100% (i.e. 100% of one isomer and none of the other), more inparticular, compounds or intermediates having a stereoisomeric excess of90% up to 100%, even more in particular having a stereoisomeric excessof 94% up to 100% and most in particular having a stereoisomeric excessof 97% up to 100%. The terms ‘enantiomerically pure’ and‘diastereomerically pure’ should be understood in a similar way, butthen having regard to the enantiomeric excess, respectively thediastereomeric excess of the mixture in question.

Pure stereoisomeric forms of the compounds and intermediates of thisinvention may be obtained by the application of art-known procedures.For instance, enantiomers may be separated from each other by theselective crystallization of their diastereomeric salts with opticallyactive acids or bases. Examples thereof are tartaric acid,dibenzoyl-tartaric acid, ditoluoyltartaric acid and camphosulfonic acid.Alternatively, enantiomers may be separated by chromatographictechniques using chiral stationary phases. Said pure stereochemicallyisomeric forms may also be derived from the corresponding purestereochemically isomeric forms of the appropriate starting materials,provided that the reaction occurs stereospecifically. Preferably, if aspecific stereoisomer is desired, said compound will be synthesized bystereospecific methods of preparation. These methods will advantageouslyemploy enantiomerically pure starting materials.

The diastereomeric racemates of the compounds of the present inventioncan be obtained separately by conventional methods. Appropriate physicalseparation methods that may advantageously be employed are, for example,selective crystallization and chromatography, e.g. columnchromatography. The present compounds may also exist in their tautomericforms. Such forms, although not explicitly indicated in the aboveformula are intended to be included within the scope of the presentinvention. For example, within the definition of Het², for example an1,2,4-oxadiazole may be substituted with a hydroxy or a mercapto groupin the 5-position, thus being in equilibrium with its respectivetautomeric form as depicted below.

The term “prodrug” as used throughout this text means thepharmacologically acceptable derivatives such as esters, amides andphosphates, such that the resulting in vivo biotransformation product ofthe derivative is the active drug as defined in the compounds of thepresent invention. The reference by Goodman and Gilman (ThePharmacological Basis of Therapeutics, 8^(th) ed, McGraw-Hill, Int. Ed.1992, “Biotransformation of Drugs”, p 13-15) describing prodrugsgenerally is hereby incorporated. Prodrugs of a compound of the presentinvention are prepared by modifying functional groups present in thecompound in such a way that the modifications are cleaved, either byroutine manipulation or in vivo, to the parent compound. For example, asubstituent containing sulfhydryl could be coupled to a carrier whichrenders the compound biologically inactive until removed by endogenousenzymes or, for example, by enzymes targeted to a particular receptor orlocation in the subject.

Prodrugs are characterized by excellent aqueous solubility, increasedbioavailability and are readily metabolized into the active inhibitorsin vivo.

The present invention is also intended to include all isotopes of atomsoccurring on the present compounds. Isotopes include those atoms havingthe same atomic number but different mass numbers. By way of generalexample and without limitation, isotopes of hydrogen include tritium anddeuterium. Isotopes of carbon include C-13 and C-14.

Whenever used hereinafter, the term “compounds of formula (I)”,“compounds of formula (II)”, “compounds of formula (III)”, “compounds offormula (IV)”, “compounds of formula (V)”, “compounds of formula (VI)”,“compounds of formula (VII)”, “compounds of formula (VIII)”, “compoundsof formulas (V) to (VIII)”, or “the compounds of present invention” orsimilar term is meant to include the compounds of general formulas (I),(II), (III), (IV), (V), (VI), (VII), (VIII), their N-oxides, salts,stereoisomeric forms, racemic mixtures, prodrugs, esters andmetabolites, as well as their quaternized nitrogen analogues. Aninteresting subgroup of the compounds of formula (V) or any subgroupthereof are the N-oxides, salts and all the stereoisomeric forms of thecompounds of formula (V).

Embodiments of the present invention are those compounds of the presentinvention or any of the subgroups thereof wherein the 4-pyridyl forms aN-oxide, for example the N-oxide of compound nr. 24.

Further embodiments of the present invention are those compounds of thepresent invention or any of the subgroups of compounds of the presentinvention wherein the compound occurs as an acid-addition salt, whereinthe salt preferably is selected from hydrochloride, hydrobromide,trifluoroacetate, fumarate, chloroacetate, methanesulfonate, oxalate,acetate and citrate.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R¹ is independentlyhydrogen, amino, mono- or disubstituted amino, wherein thesubstituent(s) of the amino may be selected from C₁₋₆alkyl,C₁₋₄alkoxyC₁₋₄alkyl, di-C₁₋₄alkylaminoC₁₋₄alkyl,piperidin-1-yl-C₁₋₄alkyl, arylC₁₋₆alkyl, wherein the aryl group may befurther substituted with C₁₋₄alkyl, or C₁₋₄alkoxy.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R¹ is independentlyhydrogen, amino, mono- or disubstituted amino, wherein thesubstituent(s) of the amino may be selected from C₁₋₄alkyl,C₁₋₄alkoxyC₁₋₄alkyl, di-C₁₋₄alkylaminoC₁₋₄alkyl, arylC₁₋₆alkyl, whereinthe aryl group may be further substituted with C₁₋₄alkoxy.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R¹ is independentlyhydrogen, amino, mono- or disubstituted amino, wherein thesubstituent(s) of the amino may be selected from C₁₋₂alkyl,C₁₋₂alkoxyC₁₋₂alkyl, di-C₁₋₂alkylaminoC₁₋₂alkyl,piperidin-1-yl-C₁₋₂alkyl, arylC₁₋₂alkyl, wherein the aryl group may befurther substituted with C₁₋₂alkoxy.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R¹ is independentlyhydrogen, amino, mono- or disubstituted amino, wherein thesubstituent(s) of the amino may be selected from methyl, methoxyethyl,dimethylaminoethyl, piperidin-1-ylethyl, benzyl, wherein the phenylgroup may be further substituted with methoxy.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R¹ is independentlyhydrogen, amino, or monosubstituted amino, wherein the substituent ofthe amino may be selected from methoxyethyl, dimethylaminoethyl,piperidin-1-ylethyl, and benzyl, wherein the phenyl group is furthersubstituted with methoxy.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R¹ is independentlyhydrogen or amino.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R⁸ is hydrogen,C₁₋₁₀alkyl, aminoC₁₋₁₀alkyl, arylC₁₋₁₀alkyl, Het¹C₁₋₆alkyl, or aprotecting group, wherein the aryl is optionally substituted with 1 to 3substituents selected from C₁₋₄alkyl, C₁₋₄alkyl-carbonyl, halo, —OR⁶,—NR^(4a)R^(4b), —SR⁵, and polyhaloC₁₋₄alkyl.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein R⁸ is hydrogen,C₁₋₆alkyl, aminoC₁₋₆alkyl, arylC₁₋₆alkyl, Het¹C₁₋₆alkyl, orC₁₋₆alkoxy-carbonyl.

Further embodiments of the present invention are those compounds offormula compounds of the present invention or any subgroup thereofwherein R⁸ is hydrogen, C₁₋₆alkyl, aminoC₁₋₄alkyl, phenylC₁₋₄alkyl,pyrrolidin-1-ylC₁₋₄alkyl, or C₁₋₆alkoxy-carbonyl.

Further embodiments of the present invention are those compounds offormula compounds of the present invention or any subgroup thereofwherein each R⁹ represents, independently, hydrogen, C₁₋₄alkyl,polyhaloC₁₋₄alkyl, halo, —COR⁶, —COOR⁷, —CONR^(4a)R^(4b), —OR⁷,—NR^(4a)R^(4b), —NR^(4a)COR⁶, —NR^(4a)SO₂R⁵, —SR⁵, or morpholin-4-yl,and wherein the C₁₋₄alkyl may be further substituted with —COOR⁷.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein each R⁹ represents,independently, hydrogen, C₁₋₄alkyl, —COR⁶, —COOR⁷, or —CONR^(4a)R^(4b),and wherein the C₁₋₄alkyl may be further substituted with —COOR⁷.

Further embodiments of the present invention are those compounds of thepresent invention or any subgroup thereof wherein each R⁹ represents,independently, hydrogen, C₁₋₄alkyl, —COR⁶, —COOR⁷, or —CONR^(4a)R^(4b).

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹¹represents hydrogen, fluoro, or pyrrolidin-1-yl.

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹¹represents hydrogen or fluoro.

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹²represents halo, C₁₋₄alkyl, or polyhaloC₁₋₄alkyl.

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹²represents halo, or polyhaloC₁₋₄alkyl.

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹²represents chloro, bromo, fluoro, or trifluoromethyl.

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹¹represents fluoro, and R¹² represents chloro, or bromo.

Further embodiments of the present invention are those compounds offormulae (V), (VI) or any of the subgroups thereof wherein R¹¹represents hydrogen, and R¹² represents chloro, bromo, fluoro, ortrifluoromethyl.

Compounds of particular interest are those compounds of formula (V)listed in Table 1 below, in particular compounds number 1, number 7,number 21, number 23, number 24, and number 25, and its N-oxides, saltsand stereoisomers.

A number of synthetic routes may be employed to produce the compounds ofthe invention. In general, they may be synthesized using reactions knownin the art. Any art-known method for synthesis may be employed. However,the following synthetic routes are convenient for preparation of theinvention compounds.

The compounds of the formula (V) may be synthesized following aprocedure adapted from Wamhoff, H.; Kroth, E. Synthesis, 1994, 405-410as described in Scheme 1.

Basically, a methyl 3-amino-2-pyrazinecarboxylate (1a) is reacted withacylchloride in the presence of a suitable solvent such as chloroform orpyridine to afford 3-acylamino-pyrazin-2-carboxylates (1b). Said3-acylaminopyrazin-2-carboxylates (1b) are converted with for exampleammonium hydroxide into 3-acylaminopyrazin-2-amides (1d). Optionally,3-acylaminopyrazine-2-carboxamides (1d) may already be obtained byacylation of 3-amino-2-pyrazinecarboxamide (1c).

The 3-acylaminopyrazin-2-amides (1d) are then cyclized by the additionof a base to form pteridin-4-ol derivatives of formula (1e). The alcoholmay then be replaced by a halogen with the help of a halogenating agentsuch as thionyl chloride in a suitable solvent like chloroform,dichloroethane or tetrahydrofuran (THF) in presence of a catalyticamount of dimethylformamide (DMF). Following, a nucleophilicsubstitution is performed on compound (1f) with an amine or an alcoholof formula HLR², together with a suitable base, such as TEA or DIPEA inan organic solvent such as DCM, THF or DMF, yielding the pteridinecompounds of formula (1g).

Alternatively, the pteridin-4-ol may be converted in a one-pot procedureinto the pteridines of formula (V) by reacting compounds of formula (1e)with an amine or alcohol of the formula HLR² together with a suitablebase, such as TEA or DIPEA in the presence ofbenzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium hexafluoro-phosphate(PyBOP). In the formula HLR², H is hydrogen, and L and R² have themeanings indicated above in the definition of the substituents ofcompound of formula (V).

Alternatively, the compounds of the formula (V) can be prepared from thecorresponding pteridinones as starting materials followed by theirconversion to the iminochlorides and the subsequent displacement of thechlorine atom with an appropriate amine such as a 4-aminopyridine asshown below in Scheme 2.

(i) thionyl chloride, DMF; (ii) 4-aminonicotinic acid methyl ester, TEA;(iii) NaOH; (iv) PyBOP, TEA, HNR^(4a)R^(4b).

Schemes 3 and 4, shown below, provide alternative routes to pyridylnucleus and further substitutions thereof.

Compounds embodied in the present invention are shown below in Table 1:

TABLE 1 # R¹ L R² R³  1 H —NH—

 2 H —N(CH₃)—

 3 H —N(CH₂CH₂CH₂CH₃)—

 4 H —N[CH₂CH₂C(CH₃)₃]—

 5 H —N(CH₂—Ph)—

 6 H —NH—

 7 H —NH—

 8 H —NH—

 9 H —NH—

10 H —N(CH₃)—

11 H —NH— —CH₂—CH₂—OH

12 H

13 H —NH—

14 H —NH—

15 H —NH—

16 H —NH—

17 H

18 H —NH—

19 H —NH—

20 H —N(CH₂CH₂CH₂NH₂)—

21 H —NH—

22 H

23 H —NH—

24 H —NH—

25 H —NH—

26 H —NH—

27 H —NH—

The manner of administration and formulation of the compounds useful inthe invention and their related compounds will depend on the nature ofthe condition, the severity of the condition, the particular subject tobe treated, and the judgment of the practitioner; formulation willdepend on mode of administration. As the compounds of the invention aresmall molecules, they are conveniently administered by oraladministration by compounding them with suitable pharmaceuticalexcipients so as to provide tablets, capsules, syrups, and the like.Suitable formulations for oral administration may also include minorcomponents such as buffers, flavoring agents and the like. Typically,the amount of active ingredient in the formulations will be in the rangeof 5%-95% of the total formulation, but wide variation is permitteddepending on the carrier. Suitable carriers include sucrose, pectin,magnesium stearate, lactose, peanut oil, olive oil, water, and the like.

The compounds useful in the invention may also be administered throughsuppositories or other transmucosal vehicles. Typically, suchformulations will include excipients that facilitate the passage of thecompound through the mucosa such as pharmaceutically acceptabledetergents.

The compounds may also be administered topically, or in formulationintended to penetrate the skin. These include lotions, creams, ointmentsand the like which can be formulated by known methods.

The compounds may also be administered by injection, includingintravenous, intramuscular, subcutaneous or intraperitoneal injection.Typical formulations for such use are liquid formulations in isotonicvehicles such as Hank's solution or Ringer's solution.

Alternative formulations include nasal sprays, liposomal formulations,slow-release formulations, and the like, as are known in the art.

Any suitable formulation may be used. A compendium of art-knownformulations is found in Remington's Pharmaceutical Sciences, latestedition, Mack Publishing Company, Easton, Pa. Reference to this manualis routine in the art.

The dosages of the compounds of the invention will depend on a number offactors which will vary from patient to patient. However, it is believedthat generally, the daily oral dosage will utilize 0.001-100 mg/kg totalbody weight, preferably from 0.01-50 mg/kg and more preferably about0.01 mg/kg-10 mg/kg. The dose regimen will vary, however, depending onthe conditions being treated and the judgment of the practitioner.

It should be noted that the compounds of the invention can beadministered as individual active ingredients, or as mixtures of severalembodiments of this formula. In addition, the compounds of the inventionmay be used as single therapeutic agents or in combination with othertherapeutic agents.

Due to their favorable antiviral properties, as will be apparent fromthe examples, the compounds of the present invention are useful in thetreatment of individuals infected by HCV and for the prophylaxis ofthese individuals. In general, the compounds of the present inventionmay be useful in the treatment of warm-blooded animals infected withflaviviruses. Conditions which may be prevented or treated with thecompounds of the present invention, especially conditions associatedwith HCV and other pathogenic flaviviruses, such as Yellow fever, Denguefever (types 1-4), St. Louis encephalitis, Japanese encephalitis, Murrayvalley encephalitis, West Nile virus and Kunjin virus. The conditionsassociated with HCV include progressive liver fibrosis, inflammation andnecrosis leading to cirrhosis, end-stage liver disease, and HCC; and forthe other pathogenic flaviruses the conditions include yellow fever,dengue fever, hemorraghic fever and encephalitis.

The compounds of the present invention or any subgroup thereof maytherefore be used as medicines against the above-mentioned conditions.Said use as a medicine or method of treatment comprises the systemicadministration to HCV-infected subjects of an amount effective to combatthe conditions associated with HCV and other pathogenic flaviviruses.Consequently, the compounds of the present invention can be used in themanufacture of a medicament useful for treating conditions associatedwith HCV and other pathogenic flaviviruses.

In an embodiment, the invention relates to the use of a compound offormula (V) or any subgroup thereof as defined herein in the manufactureof a medicament for treating or combating infection or diseaseassociated with HCV infection in a mammal. The invention also relates toa method of treating a flaviviral infection, or a disease associatedwith flavivirus infection comprising administering to a mammal in needthereof an effective amount of a compound of formula (V) or a subgroupthereof as defined herein.

In another embodiment, the present invention relates to the use offormula (V) or any subgroup thereof as defined herein for themanufacture of a medicament useful for inhibiting HCV activity in amammal infected with flaviviruses, in particular HCV. In anotherembodiment, the present invention relates to the use of formula (V) orany subgroup thereof as defined herein for the manufacture of amedicament useful for inhibiting HCV activity in a mammal infected withflaviviruses, wherein said HCV is inhibited in its replication.

Also, the combination of previously known anti-HCV compound, such as,for instance, interferon-α (IFN-α), pegylated interferon-α and/orribavirin, and a compound of the present invention can be used as amedicine in a combination therapy. The term “combination therapy”relates to a product containing mandatory (a) a compound of the presentinvention, and (b) optionally another anti-HCV compound, as a combinedpreparation for simultaneous, separate or sequential use in treatment ofHCV infections, in particular, in the treatment of infections with HCVtype 1. Thus, to combat or treat HCV infections, the compounds of thisinvention may be co-administered in combination with for instance,interferon-α (IFN-α), pegylated interferon-α and/or ribavirin, as wellas therapeutics based on antibodies targeted against HCV epitopes, smallinterfering RNA (Si RNA), ribozymes, DNAzymes, antisense RNA, smallmolecule antagonists of for instance NS3 protease, NS3 helicase and NSSBpolymerase.

Accordingly, the present invention relates to the use of a compound offormula (V) or any subgroup thereof as defined above for the manufactureof a medicament useful for inhibiting HCV activity in a mammal infectedwith HCV viruses, wherein said medicament is used in a combinationtherapy, said combination therapy preferably comprising a compound offormula (V) and (pegylated) IFN-α and/or ribavirin.

It will be appreciated by the person skilled in the art that thecompounds of formula (V) may be tested in a cellular HCV replicon systembased on Lohmann et al. (1999) Science 285:110-113, with the furthermodifications described by Krieger et al. (2001) Journal of Virology 75:4614-4624 (incorporated herein by reference), which is furtherexemplified in the examples section. This model, while not a completeinfection model for HCV, is widely accepted as the most robust andefficient model of autonomous HCV RNA replication currently available.Compounds exhibiting anti-HCV activity in this cellular model areconsidered as candidates for further development in the treatment of HCVinfections in mammals. It will be appreciated that it is important todistinguish between compounds that specifically interfere with HCVfunctions from those that exert cytotoxic or cytostatic effects in theHCV replicon model, and as a consequence cause a decrease in HCV RNA orlinked reporter enzyme concentration. Assays are known in the field forthe evaluation of cellular cytotoxicity based for example on theactivity of mitochondrial enzymes using fluorogenic redox dyes such asresazurin. Furthermore, cellular counter screens exist for theevaluation of non-selective inhibition of linked reporter gene activity,such as firefly luciferase. Appropriate cell types can be equipped bystable transfection with a luciferase reporter gene whose expression isdependent on a constitutively active gene promoter, and such cells canbe used as a counter-screen to eliminate non-selective inhibitors. Allpatents, patent applications and articles referred to before or beloware incorporated herein by reference.

EXAMPLES

The following examples are intended to illustrate, but not to limit theinvention.

Example 1 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(4-pyridylamino)pteridine, Compound No. 1

3-(5-bromo-2-fluorobenzoylamino)pyrazine-2-carboxylic acid methyl ester102

Pyridine (7.75 g, 98.0 mmol) was added at 0° C. under N₂ to a solutionof 3-amino-pyrazine-2-carboxylic acid methyl ester 101 (1.5 g, 9.80mmol) and 5-bromo-2-fluorobenzoylchloride (9.45 g, 49.0 mmol) in CH₂Cl₂.The reaction mixture was warmed at 40° C. for 4 h, then cooled down atroom temperature. The reaction mixture was quenched with 20 mL ofethanol, evaporated, partitioned between CH₂Cl₂ and 1N NaHCO₃, dried(Na₂SO₄) and evaporated. The crude material was triturated in EtOH,filtered, washed with EtOH and ether to give 2.6 g of3-(5-bromo-2-fluorobenzoyl-amino)pyrazine-2-carboxylic acid methyl ester102 as a white powder (LCMS analysis).

3-(5-bromo-2-fluorobenzoylamino)pyrazine-2-carboxamide 103

A mixture of 3-(5-bromo-2-fluorobenzoylamino)pyrazine-2-carboxylic acidmethyl ester 102 (2.6 g, 7.34 mmol) and NH₄OH (15 mL) in ethanol (50 mL)was heated at reflux for 10 min. Then, the reaction mixture was cooledat room temperature and the precipitate was filtered off, washed withethanol and ether to give 2.1 g of the title product 103 as a whitepowder (LCMS analysis).

2-(5-bromo-2-fluorophenyl)pteridin-4-one 104

A mixture of 3-(5-bromo-2-fluorobenzoylamino)pyrazine-2-carboxamide 103(2.3 g, 6.78 mmol) and KOH (3.81 g, 67.8 mmol) in H₂O (60 mL) and DMSO(20 mL) was stirred at room temperature for 45 min. Acidification to pH5 (pH paper control) with AcOH followed by addition of 50 mL of ice-coldwater afforded a precipitate, which was filtered off, washed with H₂O,acetonitrile and ether to give 1.83 g of the title product 104 as awhite powder (LCMS analysis).

2-(5-bromo-2-fluorophenyl)-4-(4-pyridylamino)pteridine, Compound No. 1

Triethylamine (1.04 mL, 7.17 mmol) was added to a solution of2-(5-bromo-2-fluoro-phenyl)pteridin-4-one 104 (800mg, 2.49 mmol),4-aminopyridine (469 mg, 4.98 mmol) and PyBOP (2.59 g, 4.98 mmol) inCH₂Cl₂. After 12 h, the reaction mixture was partitioned betweenCH₂Cl₂/Petroleum ether (2:1, 300 mL) and ice-cold 1N HCl (300 mL). ThepH of the water phase was adjust to 12 with conc. NaOH and extractedwith AcOEt, dried (Na₂SO₄) and evaporated. The residue was triturated inCH₂Cl₂/Petroleum ether (2:1, 15 mL), filtered off, and washed withether. The product was purified by column chromatography(AcOEt/CH₂Cl₂/MeOH, 5:4:1) to give 325 mg of the title product 1 as ayellow powder (LCMS analysis).

Example 2

Synthesis of 4-[[2-(5-Bromo-2-fluorophenyl)pteridin-4-yl]amino]nicotinicacid, compound no. 16, and 4-[[2-(5-bromo-2-fluorophenyl)pteridin-4-yl]amino]-N-[3-(2-oxopyrrolidin-1-yl)propyl]nicotinamide,Compound No. 21

2-(5-Bromo-2-fluorophenyl)-4-Chloropteridine 106

Thionyl chloride (371 mg, 3.11 mmol) was added to the stirred suspensionof 2-(5-bromo-2-fluorophenyl)pteridin-4-one 104 (200 mg, 0.623 mmol) inchloroform (5 mL) and dry DMF (100 μL). The reaction mixture wasrefluxed under nitrogen for 1 h (starting material gone by HPLC). Thesolvent was removed in vacuo. Then the residue was triturated in Et₂Oand filtered off to give 210 mg of the title product 106 as a yellowsolid (LCMS analysis).

4-[[2-(5-Bromo-2-fluorophenyl)pteridin-4-yl]amino]nicotinic Acid MethylEster 107

To a solution of 2-(5-bromo-2-fluorophenyl)-4-chloropteridine 106 (200mg, 0.589 mmol), 4-aminonicotinic acid methyl ester (224 mg, 1.47 mmol)in dichloroethane (5 mL), was added dropwise triethylamine (300 μL, 2.07mmol). The resulting mixture was heated at 70° C. for 15 min, thenquenched with silica and purified by column chromatography(AcOEt/CH₂Cl₂/triethylamine, 70/19/1). Crystallization from AcOEt/Et₂Oafforded 200 mg of the title product 107 as yellow prisms (LCMSanalysis).

4-[[2-(5-Bromo-2-fluorophenyppteridin-4-yl]amino]nicotinic acid 16

A solution of4-[[2-(5-bromo-2-fluorophenyl)pteridin-4-yl]amino]nicotinic acid methylester 107 (200 mg, 0.439 mmol) and NaOH (44 mg, 1.10 mmol) inTHF/MeOH/H₂O (3:2:1, 5 mL), was stirred at room temperature for 3 h. Thesolvent was evaporated, and the residue dissolved in H₂O, neutralizedwith AcOH, filtered off, and successively washed with H₂O, MeOH andEther to give 160 mg of the title product 16 as a yellow powder (LCMSanalysis).

4-[[2-(5-bromo-2-fluorophenyl)pteridin-4-yl]amino]-N-[3-(2-Oxopyrrolidin-1-yl)-propyl]nicotinamide21

Triethylamine (140 μL, 1.00 mmol) was slowly added to a solution of4-[[2-(5-bromo-2-fluorophenyl)pteridin-4-yl]amino]nicotinic acid 16 (150mg, 0.340 mmol), PyBOP (0.350 mg, 0.68 mmol), and1-(3-aminopropyl)pyrrolidinone (97 mg, 0.68 mmol) in CH₂Cl₂ (10 mL).After 15 min at room temperature, the reaction mixture was evaporatedand the residue purified by column chromatography (AcOEt/CH₂Cl₂, 2:1+1%triethylamine to AcOEt/CH₂Cl₂/MeOH, 7:2:1+1% triethylamine). The yellowpowder was recrystallized from EtOH to give 58 mg of the title product21 as yellow prisms (LCMS analysis).

Example 3 Synthesis of2-(5-Bromo-2-pyrrolidin-1-ylphenyl)-4-(3-methyl-4-pyridylamino)pteridine,Compound No. 6

2-(5-Bromo-2-pyrrolidin-1-ylphenyl)pteridin-4-one 110

A solution of 2-(5-bromo-2-fluorophenyl)pteridin-4-one 104 inpyrrolidine was heated in a microwave cavity (Power=270 W, Temp=110° C.)for 12 min. The pyrrolidine was evaporated, then residue partitionedbetween NaHCO₃ 0.5 N and CH₂Cl₂, dried (Na₂SO₄) and evaporated.Trituration in Et₂O afforded the title product 110 as a yellow powder(LCMS analysis).

2-(5-Bromo-2-pyrrolidin-1-ylphenyl)-4-(3-methyl-4-pyridylamino)pteridine6

The title product was synthesized by reaction of the2-(5-bromo-2-pyrrolidin-1-yl-phenyl)pteridin-4-one 110 and4-amino-3-methylpyridine following the procedure described for4-(4-pyridylamino)-2-(5-bromo-2-fluorophenyl)pteridine 1 (LCMSanalysis).

Example 4 Synthesis of4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine,Compound No. 3

4-butylaminopyridine 113

A solution of 4-chloropyridine (2.0 g, 17.6 mmol), 50% butylamine inwater (30 mL) was heated at 150° C. in a sealed tube for 24 h. Thereaction mixture was evaporated, partitioned between 0.1 N NaOH andCH₂Cl₂, dried (Na₂SO₄) and evaporated. Crystallization inether/petroleum ether 4:1 afforded 2.4 g of the title product 113 as awhite powder (LCMS analysis).

4-[(butyl)(4-pyridypamino]-2-(5-bromo-2-fluorophenyl)pteridine 3

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with 4-butylaminopyridine113 following the procedure described for4-(4-pyridylamino)-2-(5-bromo-2-fluorophenyl)pteridine 1 (LCMSanalysis).

Example 5

Synthesis of 2-(3-fluorophenyl)-4-(4-pyridylamino)pteridine, CompoundNo. 27

The title product was synthesized by reaction of the2-(3-fluorophenyl)pteridin-4-one with 4-aminopyridine following theprocedure described for4-[(butyl)(4-pyridyl)-amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 6 Synthesis of2-(5-bromo-2-fluorophenyl)-4-[(methyl)(4-pyridyl)amino] pteridine,Compound No. 2

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-(methylamino)pyridine following the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluoropheny)pteridine 3.

Example 7 Synthesis of2-(5-bromo-2-fluorophenyl)-4-[(3,3-dimethylbutyl)(4-pyridyl)amino]pteridine, Compound No. 4

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-(3,3-dimethylbutylamino)pyridine following the procedure described for4-[(butyl)(4-pyridy)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 8 Synthesis of4-[(benzyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl) pteridine,Compound No. 5

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-(benzylamino)pyridine following the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 9 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(3-methyl-4-pyridylamino) pteridine,Compound No. 7

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-amino-3-methylpyridine following the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 10 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(phenylamino)pteridine, Compound No. 8

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with aniline following theprocedure described for4-[(butyl)-(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 11 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(2-tolylamino)pteridine, Compound No. 9

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with 2-methylanilinefollowing the procedure described for4-[(butyl)(4-pyridypamino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 12 Synthesis of2-(5-bromo-2-fluorophenyl)-4[4-(2-pyridyl)piperazin-1-yl]pteridine,Compound No. 12

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with1-(2-pyridyl)piperazine following the procedure described for4-[(butyl)(4-pyridypamino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 13 Synthesis of2-(5-bromo-2-fluorophenyl)-4-[(methyl)(phenyl)amino]pteridine, CompoundNo. 10

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with N-methylanilinefollowing the procedure described for4-[(butyl)(4-pyridy)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 14 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(2-hydroxyethylamino)pteridine, CompoundNo. 11

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with 2-hydroxyethylaminefollowing the procedure described for4-[(butyl)(4-pyridy)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 15 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(4-morpholinophenylamino) pteridine,Compound No. 14

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-(4-morpholino)aniline following the procedure described for4-[(butyl)(4-pyridy)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 16 Synthesis of2-(5-bromo-2-fluorophenyl)-4-(2-methyl-4-pyridylamino)pteridine,Compound No. 15

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-amino-2-methylpyridine following the procedure described for4-[(butyl)(4-pyridy)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 17 Synthesis of2-(5-bromo-2-fluorophenyl)-4-[[2-(pyrrolidin-1-yl)ethyl]-(4-pyridyl)-amino]pteridine,Compound No. 17

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-[2-(pyrrolidin-1-yl)ethylamino]pyridine following the proceduredescribed for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)-pteridine 3.

Example 18 Synthesis of2-(5-bromo-2-fluorophenyl)-4-[(phenethyl)(4-pyridyl)amino]-pteridine,Compound No. 22

The title product was synthesized by reaction of the2-(5-bromo-2-fluorophenyl)-pteridin-4-one 104 with4-(phenethylamino)pyridine following the procedure described for4-[(butyl)(4-pyridy)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 19 Synthesis of2-(2-methyl-6-pyridyl)-4-[(3-methyl-4-pyridyl)amino]pteridine, CompoundNo. 19

The title product was synthesized by reaction of the2-(2-methyl-6-pyridyl)pteridin-4-one with 4-amino-3-methylpyridinefollowing the procedure described for4-[(butyl)-(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 20 Synthesis of 2-(3-chlorophenyl)-4-(4-pyridylamino)pteridine,Compound No. 18

The title product was synthesized by reaction of the2-(3-chlorophenyl)pteridin-4-one with 4-aminopyridine following theprocedure described for4-[(butyl)(4-pyridyl)-amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 21 Synthesis of2-(5-chloro-2-fluorophenyl)-4-(3-ethyl-4-pyridylamino)pteridine,Compound No. 23

The title product was synthesized by reaction of the2-(5-chloro-2-fluorophenyl)-pteridin-4-one with 4-amino-3-ethylpyridinefollowing the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 22 Synthesis of2-(5-chloro-2-fluorophenyl)-4-(3-methyl-4-pyridylamino)pteridine,Compound No. 25

The title product was synthesized by reaction of the2-(5-chloro-2-fluorophenyl)-pteridin-4-one with 4-amino-3-methylpyridinefollowing the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 23 Synthesis of2-(5-chloro-2-fluorophenyl)-4-(4-pyridylamino)pteridine, Compound No. 24

The title product was synthesized by reaction of the2-(5-chloro-2-fluorophenyl)-pteridin-4-one with 4-aminopyridinefollowing the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

Example 24 Synthesis of2-(3-trifluoromethylphenyl)-4-(4-pyridylamino)pteridine, Compound No. 26

The title product was synthesized by reaction of the2-(3-trifluoromethylphenyl)-pteridin-4-one with 4-aminopyridinefollowing the procedure described for4-[(butyl)(4-pyridyl)amino]-2-(5-bromo-2-fluorophenyl)pteridine 3.

In Table 2 below, the LCMS data for the synthetized compounds is shown:

Compound Number LCMS data 1 m/z : 397, 398, 399, 400 RT: 2.30 13 m/z :455, 456, 457, 458, RT: 4.06 21 m/z: 565, 566, 567, 568, RT: 3.12 6 m/z: 462, 463, 464, 465, RT: 2.73 3 m/z : 453, 454, 455, 456, RT: 3.45 2m/z : 411, 412, 413, 414, RT = 2.49 4 m/z : 481, 482, 483, 484, RT =4.23 5 m/z : 487, 488, 489, 490, RT: 3.49 7 m/z : 411, 412, 413, 414,RT: 2.49 8 m/z: 396, 397, 398, 399, RT: 4.52 9 m/z : 410, 411, 412, 413,RT: 4.59 12 m/z : 466, 467, 468, 469, RT: 3.31 10 m/z : 410, 411, 412,413, RT: 4.70 11 m/z : 364, 365, 366, 367, RT = 2.67 14 m/z : 419, 420,RT: 4.27 15 m/z: 411, 412, 413, 414, RT: 2.49 22 m/z: 501, 502, RT: 3.5019 m/z : 330, RT: 1.40 18 m/z : 335, 336, 337, RT: 2.37 25 m/z : 367,368, 369, RT: 2.44 24 m/z : 353, 354, 355, RT: 2.29 m/z is themass-to-charge ratio RT is the retention time

Example 25 Activity of Compounds of Formula (V) in HCV Replicon Assays

Stable Replicon Cell Reporter Assays:

The compounds of the present invention are examined for activity in theinhibition of HCV RNA replication in a cellular assay. The assaydemonstrates that the present compounds exhibit activity against HCVreplicons functional in a cell culture. The cellular assay is based on abicistronic expression construct, as described by Lohmann et al. (1999)Science vol. 285 pp. 110-113 with modifications described by Krieger etal. (2001) Journal of Virology 75: 4614-4624, in a multi-targetscreening strategy. In essence, the method is as follows.

The assay utilizes the stably transfected cell line Huh-7 luc/neo(hereafter referred to as Huh-Luc). This cell line harbors an RNAencoding a bicistronic expression construct comprising the wild typeNS3-NSSB regions of HCV type lb translated from an Internal RibosomeEntry Site (IRES) from encephalomyocarditis virus (EMCV), preceded by areporter portion (FfL-luciferase), and a selectable marker portion(neo^(R), neomycine phosphotransferase). The construct is bordered by 5′and 3′ NTRs (non-translated regions) from HCV type 1b. Continued cultureof the replicon cells in the presence of G418 (neo^(R)) is dependent onthe replication of the HCV RNA. The stably transfected replicon cellsthat express HCV RNA, which replicates autonomously and to high levels,encoding inter alia luciferase, are used for screening the antiviralcompounds.

Cellular Assay Experimental Method:

The replicon cells are plated in 384 well plates in the presence of thetest and control compounds which are added in various concentrations.Following an incubation of three days, HCV replication is measured byassaying luciferase activity (using standard luciferase assay substratesand reagents and a Perkin Elmer ViewLux™ ultraHTS microplate imager).Replicon cells in the control cultures have high luciferase expressionin the absence of any inhibitor. The inhibitory activity of the compoundon luciferase activity is monitored on the Huh-Luc cells, enabling adose-response curve for each test compound. EC50 values are thencalculated, which value represents the amount of the compound requiredto decrease by 50% the level of detected luciferase activity, or morespecifically, the ability of the genetically linked HCV replicon RNA toreplicate.

The compounds tested were found to have activities as follows:

TABLE 3 HCV Replicon Compound activity Number (μM) 1 0.352 13 4.9 210.058 6 18 3 2.2 27 3.0 2 3.65 4 0.48 5 0.99 7 0.95 8 >32 9 11 12 >32 1011 11 >32 14 8.7 15 3.56 22 1.96 19 12 18 1.5 23 0.52 25 0.48 24 0.78 262.0

Example 26 Pharmacokinetic Profile of Compound No. 21 in Male Swiss SPF(CDM)-Mice

Compound nr. 21 was dissolved in a 10% hydroxypropyl-β-cyclodextrin(HP-β-CD) solution at a final concentration of 1 mg base-eq./ml, .pH4.36.

Three animals were administered orally the solution of compound nr. 21to obtain a dose of 20 mg base-eq./kg. Blood samples were taken at 30min, 1, 2, 4, 8 and 24 h after oral dose administration. Plasma wasobtained following centrifugation at 4° C. for 10 minutes atapproximately 1900×g.

From each orally dosed animal individual samples of heart and liver weredissected and weighed. Tissue samples were homogenized in demineralizedwater.

Plasma and tissue samples were analysed for compound nr. 21, using aqualified research LC-MS/MS method.

A limited pharmacokinetic analysis was performed using WinNonlin™Professional (Version 4.0.1). A non-compartmental analysis using thelin/log trapezoidal rule with lin/log interpolation was used for alldata. The variability between animals is indicated by the standarddeviation (st dev).

An overview of the mean plasma and tissue concentrations and some basicpharmacokinetic parameters can be found in Table 4 and FIG. 1.

Conclusion: The analysed concentration of the oral formulation was 1.0mg base-eq./ml resulting in an exact dose of 20 mg base-eq./kg orally.No stability problems were observed on the day of dosing.

Plasma

After a single oral administration of the compound nr 21 at 20 mgbase-eq./kg levels were quantifiable up to 8 h post dose (Table 4 andFIG. 1). The mean maximum plasma concentration (C_(max)) was 220 ng/mlobserved at 0.5 h post dose (T_(max)), indicating a rapid absorption ofthe compound. The mean half-life (t_(1/2 (2-8 h))) was 2.9 h. Theexposure as calculated by AUC_(0-inf) was 332 ng.h/ml.

Tissue

As can be seen in FIG. 1, the studied tissues together with plasma hadquite similar concentration time profiles, indicating distributionequilibrium between plasma and tested tissues. The mean maximum tissueconcentrations (C_(max)) were achieved at the same time as in plasma at0.5 h post dose, indicating a rapid equilibrium. The highestconcentration was observed in the liver (4057 ng/g) followed by heart(678 ng/g) with a tissue to plasma ratios of 24 and 3.8 respectively(Table 4 and FIG. 1). The mean half-life (t_(1/2(2-8h))) estimated forthe liver was 3.5 h and 3.4 h for the heart which was comparable withthat of plasma (2.9 h). Tissue levels declined in a similar pattern toplasma and at 8 h post dose only low levels of the compound were stilldetectable, indicating no major evidence for retention.

TABLE 4 Mean plasma and tissue levels (n = 3) together with some basicpharmacokinetic parameters of compound nr. 21 after a single oraladministration at 20 mg base-eq./kg in the male Swiss SPF (CD1)-miceCompound nr. 21 (ng/ml or g/ml) Time Plasma stdev Heart stdev Liverstdev 0.5 220 ±100  678 ±258  4057 ±1730 1 166 ±160  557 ±403  2937±1852 2 21.7 ±6.7  92.9 ±49.9 611 ±131  4 20.3 ±5.1  83.6 ±35.9 627±189  8 5.52 ±1.20 29.1 ±6.0  201 ±59  24 BQL ¹⁾ BQL ¹⁾ BQL ¹⁾ C_(max)(ng/ml) 220 678 4057 T_(max) (h) 0.5 0.5 0.5 t_(1/2 (2-8 h)) (h) 2.9 3.43.5 AUC₍₀₋₈₎(ng · h/ml) 309 1119 6965 AUC_(0-inf) (ng · h/ml) 332 12627973 Ratio tissue/plasma — 3.8 ²⁾ 24 ²⁾ ¹⁾ BQL = below the limit ofquantification. LLOQ was 0.500 ng/ml for plasma and ranged between 5.00and 13.16 ng/g for tissue. ²⁾ value based upon the AUC_(inf)

1-21. (canceled)
 22. A compound of the formula (VII):

or a salt, stereoisomeric form, or racemic mixture thereof, wherein R¹is hydrogen; R⁸ is hydrogen and R⁹ is C₁₋₄alkyl, —COR⁶, COOR⁷, or—CONR^(4a)R^(4b); or R⁸ is C₁₋₆alkyl or phenylC₁₋₄alkyl and R⁹ ishydrogen, C₁₋₄alkyl, —COR⁶, COOR⁷, or —CONR^(4a)R^(4b); R⁶ isindependently hydrogen, or C₁₋₄alkyl; each R⁷ is independently hydrogen,or C₁₋₄alkyl; and each R^(4a) and R^(4b) is independently hydrogen,C₁₋₄alkyl,
 23. The compound according to claim 22, wherein R⁸ ishydrogen and R⁹ is —C₁₋₄alkyl, —COR⁶, —COOR⁷, or —CONR^(4a)R^(4b). 24.The compound according to claim 23, wherein R⁹ is —CONR^(4a)R^(4b). 25.The compound according to claim 22, wherein R⁸ is C₁₋₆alkyl orphenylC₁₋₄alkyl and R⁹ is hydrogen, C₁₋₄alkyl, —COR⁶, COOR⁷, or—CONR^(4a)R^(4b).
 26. The compound according to claim 25, wherein R⁸ isC₁₋₆alkyl and R⁹ is hydrogen.
 27. The compound according to claim 25,wherein R⁸ is phenylC₁₋₄alkyl and R⁹ is hydrogen.
 28. The compoundaccording to claim 22 of the formula (VIII):


29. The compound according to claim 28, wherein R⁸ is hydrogen and R⁹ is—C₁₋₄alkyl, —COR⁶, —COOR⁷, or —CONR^(4a)R^(4b).
 30. The compoundaccording to claim 28, wherein R⁸ is C₁₋₆alkyl or phenylC₁₋₄alkyl and R⁹is hydrogen, C₁₋₄alkyl, —COR⁶, COOR⁷, or —CONR^(4a)R^(4b).
 31. Thecompound according to claim 30, wherein R⁸ is C₁₋₆alkyl and R⁹ ishydrogen. 32, The compound according to claim 22 that is


33. A pharmaceutical composition comprising a compound according toclaim 22 and a pharmaceutically acceptable excipient.
 34. Thepharmaceutical composition according to claim 33, further comprising oneor more other anti-hepatitis C virus agents.